“On a steamy morning last week Mark Dimunation, the chief of the rare book and special collections division at the Library of Congress, was in a windowless basement room here at the University of Virginia, leading a dozen people in a bibliophile’s version of the wave.He lined up the group and handed each person a sheet of copier paper with a syllable written on it. After a few halting practice runs — “Hip-na-rah-toe …” — the group successfully shouted out, “ ‘Hypnerotomachia Poliphili,’ 1499!”